IQAASL is a project sponsored by the Swiss Federal Office for the Environment to quantify shoreline trash along swiss lakes and rivers. Multiple small scale litter surveys are completed at different locations within a designated survey area. For the year 2020/2021 the survey areas were defined by the municipalities that border the Aare, Rhône, Ticino and Linth/Limmat rivers and any lakes or rivers that contribute to one of these rivers.
A litter survey is the identification and count of all anthropogenic objects found within a delimited area, in this study all surveys were bordered on one side by water (a river or lake). Each object is placed into one of 260 categories¹. The location, date, survey dimensions and the total number of objects in each category is noted.
The survey results help ALL stakeholders identify the items that make up the mass of trash found in the natural environment and where those objects are most likely to be found. The surveys answer the following questions:
These are the most frequently asked questions and should be considered when determining any mitigation or reduction strategies.
Summarize the results for the water feature and define the magnitude of those results with respect to the rest of the survey area.
Scope: description of water feature
Survey dimensions: locations, aggregated totals
Trash removed: the most abundant objects
Trash removed: the most frequent
For more information about the project visit project home.
If you would like more information about this survey area please contact:
¹ The EU guide on monitoring marine litter
² There is most likely more trash at the survey site, but certainly not less than what was recorded.
³ Independent observations : stats stackexchange
Some objects are found often and in elevated quantities, others are found often and in small quantities and some objects are found less often but in large quantities. Knowing the diffference can help find the sources.
Note The survey area results include the results from the current water feature
The utility type is based on the utilisation of the object prior to it being discarded. Objects that are found are placed into to one of the 260 categories. Those categories are grouped according to utilisation.
For example, a piece of plastic could be placed into the category 'Fragmented plastics', depending on its size. However, a piece of plastic that was once a bucket and we know this because we are familiar with either the brand or the product or if we recognize it as a piece of a bucket it is placed in the code for buckets⁸.
⁸ See the annex for the complete list of objects identified, includes category and group classification - the code for a buckets is G57
Contact analyst@hammerdirt.ch for any questions about the content of this report. If you would like a report for your municipality contact the Swiss federal office for the environment: Municipal waste section.
The survey results for the most abundant objects were ranked against population and three other criteria for each survey location. Within a radius of 1500m of each survey location the following characteristics were calculated:
buildings: m² of surface area attributed to buildings
streets: length in meters of all roads
number of stream/river discharge points
The three attributes were evaluated seperately and combined - urbanization. Urbanization is the weighted value of the sum of population, buildings and streets for each survey. The values were evaluated using the Spearmans rank correlation with p= 0.1. The results can be interpreted in the following way:
" + " - positive correlation: the chances of finding the object and the quantity found were increased as the amount of the attrubute increased within 1500m the survey area.
" - " - negative correlation: neither the chances or the quantity of finding the object found were increased by this attribute, and previously it was found in greater quantities when this atribute was minimized within 1500m of the survey area.
" NA " - no effect: there is no statistical basis to reject a null effect by this attribute based on the current results.
Important! Results vary for each location and at each survey. A correlation is not a sign of causation.